Group 1 and 7 Flashcards
What happens to reactivity as you go down Group 1
Reactivity increases
Why does reactivity increase as you go down Group 1
- Group 1 metals want to lose their outer electron to achieve a full outer shell.
- As you down the group the atoms are larger so have more shielding and distance from the nucleus
- Therefore less attraction to positive nucleus so e- is more easily lost
Write the word equation for when a group 1 metal reacts with oxygen
metal + oxygen -> metal oxide
What type of reaction is it when oxygen reacts with a group 1 metal
oxidation
What happens when Li reacts with oxygen and what oxide is formed
Burns crimson/red flame to form a white solid. Lithium oxide (Li2O) is formed
What happens when Na reacts with oxygen and what oxide is formed
Burns yellow flame to form a white solid. Sodium oxide (Na2O) is formed
What happens when K reacts with oxygen and what oxide is formed
Burns lilac flame to form a white solid. Potassium oxide (K2O) is formed
What happens when an oxide is dissolved into water
An alkaline solution is formed
Why is the solution alkaline
the OH- ions
Write the word equation for when a Group 1 metal reacts with water
metal + water -> metal hydroxide + hydrogen
What happens when Lithium reacts with water and what product is formed
- Moves and floats on the surface
- Effervescence as gas H2
- Eventually disappears
- Lithium hydroxide + hydrogen is formed
What happens when sodium reacts with water and what product is formed
- Whizzes and floats on surface
- Effervescence as gas H2
- Eventually disappears
- Melts into a ball
- Sodium hydroxide + hydrogen is formed
What happens when Potassium reacts with water and what product is formed
- Whizzes and floats on surface
- Effervescence as gas H2
- Eventually disappears
- Melts into a ball
- H2 gas ignites and burns as a lilac flame
- Potassium hydroxide + hydrogen is formed
How are group 1 metals different to typical metals:
- soft, can be cut by a knife
- Low density
- Low boiling and melting points
How are group 1 metals similar to other metals
- Good conductors
- Shiny (when freshly cut)
What are trends going down group 1
- Bigger atoms
- More reactive
- More dense
- Lower m.p and b.p
- Softer to cut
How do halogens exist
As covalently bonded diatomic molecules
What is the colour and state of fluorine
Pale yellow
Toxic gas
What is the colour and state of chlorine
pale green
toxic gas
What is the colour and state of bromine
red-brown
volatile liquid
What is the colour and state of iodine
grey crystalline
solid
What happens to reactivity as you go down group 7
It decreases
What happens to melting point and boiling point as you go down group 7
it increases
What happens to iodine when heated
It sublimes to a purple vapour
What happens to the size of the atom going down group 7
They are bigger because the have one extrea sell of electrons
Why does group 7 become less reactive going down
Atoms get larger and less reactive down group
Outer shell gets further from nucleus and is shielded by more electrons
Therefore decreased attraction to positive nucleus so harder to attract anothe electron to complete outer shell
Hence reactivity decreases
Why is there an increase in melting point and boiling point
Because the attraction between the molecules (intermolecular forces) increase as the molecules get bigger. Increased IMF means more energy required to melt/ boil
